King, who is an independent, said Republican Collins is "exactly what we need in the Senate."

The endorsement came following a speech by King at the Margaret Chase Smith Library in Skowhegan. The library hosted a conference on bipartisanship Friday.

Sen.Collins said King contacted her recently to offer his endorsement, and that she was very glad to accept it. The two Senators, one Republican, the other Independent, have worked closely together on a range of issues since Sen. King took office.

Collins' chief of staff, Steve Abbott, said he is not aware of another instance in modern Maine political history where one Senator has received such a public endorsement from another.

Sen. King will endorse Sen. Jeanne Shaheen of New Hampshire Friday afternoon.